Efficient Removal of Methane over Cobalt-Monoxide-Doped AuPd Nanocatalysts

To overcome deactivation of Pd-based catalysts at high temperatures, we herein design a novel pathway by introducing a certain amount of CoO to the supported Au–Pd alloy nanoparticles (NPs) to generate high-performance Au–Pd– x CoO/three-dimensionally ordered macroporous (3DOM) Co 3 O 4 ( x is the Co/Pd molar ratio) catalysts. The doping of CoO induced the formation of PdO–CoO active sites, which was beneficial for the improvement in adsorption and activation of CH 4 and catalytic performance. The Au–Pd–0.40CoO/3DOM Co 3 O 4 sample performed the best ( T 90% = 341 °C at a space velocity of 20 000 mL g –1 h –1 ). Deactivation of the 3DOM Co 3 O 4 -supported Au–Pd, Pd–CoO, and Au–Pd– x CoO nanocatalysts resulting from water vapor addition was due to the formation and accumulation of hydroxyl on the catalyst surface, whereas deactivation of the Pd–CoO/3DOM Co 3 O 4 catalyst at high temperatures (680–800 °C) might be due to decomposition of the PdO y active phase into aggregated Pd 0 NPs. The Au–Pd– x CoO/3DOM Co 3 O 4 nanocatalysts exhibited better thermal stability and water tolerance ability compared to the 3DOM Co 3 O 4 -supported Au–Pd and Pd–CoO nanocatalysts. We believe that the supported Au–Pd– x CoO nanomaterials are promising catalysts in practical applications for organic combustion.